JPS6068893A - Drive apparatus of automatic sewing machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a drive device for an automatic sewing machine that moves a presser foot holding cloth in a fixed shape using a memory element such as a PIIOM to obtain a seam of a fixed shape. In particular, the present invention relates to a drive device for an automatic sewing machine that can suppress vibration fIl+ of a presser foot device in an automatic cloth feeding sewing machine.

[Prior art]

An example of the drive device of a conventional automatic sewing machine is shown in FIG. This is a detector that generates up position and needle down position signals. 3 is a sewing machine motor that rotates the sewing machine; 4 is a sewing machine driver that drives this sewing machine motor 3; these constitute a driving device that drives the sewing machine.

5.6 is a pulse motor that drives a presser device (not shown) that clamps the workpiece in each of orthogonal X and Y directions;
These constitute the XY drive mechanism section 7. Reference numerals 8 and 9 denote pulse motor drivers for driving the pulse motors 5 and 6, respectively. Reference numeral 10 denotes a feed pulse train generation circuit that supplies a feed pulse train corresponding to the stitch length to the pulse drivers 8 and 9. Together with the motors 5 and 6, it constitutes a positioning drive device.

11 is a sewing machine start switch (sewing machine switch), 1
2 is a switch that moves the presser foot up and down; 13 is a central processing unit (hereinafter referred to as CI U) that controls each part; 1
4.15 is a data input/output port, 16 is a system control memory, 17 is a data temporary memory, 18 is a pattern data memory, 19 is a data bus, 20 is an address bus, 21 is an output and input/output of the pulse train generation circuit 10 This is an AND gate which takes the output of the boat 15 as inputs 21b and 21a, and performs the logical product of these two inputs and passes the cipher train.

The sewing machine 1 that forms the stitches, the drive device that drives the sewing machine 1, the positioning device that positions the presser foot device that clamps the workpiece based on pre-programmed data, and the control that controls each of these devices. The sewing machine is equipped with a sewing machine CI) U, and is configured to drive the presser foot intermittently in synchronization with the rotation of the sewing machine 1 according to the data.

- The operation of the drive device for the automatic sewing machine configured as described above will be explained.

First, when the presser foot switch 12 is stepped on, the presser foot is turned downward, and the workpiece to be sewn is clamped by the presser foot. And the sewing machine switch (sewing machine start switch)
11, the sewing machine driver 4 is driven through the input/output boat 14, whereby the sewing machine motor 3 starts to rotate and the sewing machine starts rotating once. At the same time,
The CPU 13 reads cloth speed data for one stitch from the turn data memory 18 into which sewing pattern data is input in synchronization with the needle down position signal of the sewing machine, and sends the data through the input/output boat 14. Ruth train generation circuit 1
Output to 0.

Next, the feed pulse train generation circuit 10 outputs a pulse corresponding to the stitch length to the input 21b of the AND gate 21 in synchronization with the needle down position signal. At this time, the input/output boat 15 outputs a "high level" to the input 21a of the AND gate 21, and the pulse train from the transmitting pulse train generation circuit 10 is output to the pulse motor driver 8.9.
The pulse motors 5 and 6 of each axis of Y are driven respectively to move the N distribution presser by a predetermined feed rate.

FIG. 2 is a block diagram showing an example of a pulse motor driver of a conventional automatic sewing machine. In the figure, 22 is a coil of a pulse motor that drives a presser foot device (not shown), 23 is a phase switching transistor, 24 is a phase switching circuit that controls the phase switching transistor 23, and 25 is a pulse motor. 26 is a box for detecting the current flowing through the coil 22 of the pulse motor; a current detection resistor; 26 is a voltage comparison circuit that detects the current flowing through the coil 22 of the pulse motor; the voltage extracted as the voltage of the current detection resistor 25 is compared with a reference voltage 27; 28 is a pulse width control circuit (hereinafter referred to as I'WM); 29 is a reference oscillation circuit that outputs a reference oscillation frequency to this PWM 28;
30 is a transistor whose on/off operation is controlled by the output of the PWfW 28; 31 is a DC power supply; 32
is a diode for 1111.

The collector of the phase switching transistor 23 is connected to the emitter of the transistor 30 via the coil 22 of the pulse motor.
, is connected to the negative electrode side of the DC π1 source 31 via the current detection resistor 25, and its base is connected to the output end of the phase switching circuit 24. In addition, the collector of the transistor 30 is connected to the DC power supply 3.
The base is connected to the output end of the PWM 28. Therefore, the connection point between the coil 22 of the pulse motor and the collector of the transistor 23 is connected to the positive terminal (ill) of the DC power supply 31 through the return diode 32 in the forward direction, and It is configured to process the back electromotive force and regenerate it to the DC power supply 31, and is configured to control the pulse width of the PWM 2B using an error signal that is the output of the voltage comparison circuit 26.

FIG. 3 serves to explain the operations of FIGS. 1 and 2.

In this time chart, (a) shows the needle bar motion of the sewing machine, Φ) shows the needle down position signal obtained by the detector 2 shown in Fig. 1, and (C) shows the needle bar motion shown in Fig. 1. The feed pulse sequence corresponding to the stitch length obtained from the input 21b of the AND gate 21, (d) shows the vibration form of the presser foot device. In Fig. 3(a), (a) shows the needle bar of the sewing machine, (b) shows the throat plate surface, and (C
), (→ and (e) indicate the cloth feeding period, and (ni) and (e) indicate the cloth feeding stop period.

Next, the operations of the automatic sewing machine shown in FIG. 1 and the pulse motor driver shown in FIG. 2 will be explained with reference to FIG. 3.

First, when the CPU 13 shown in FIG. 1 of the automatic sewing machine detects that the sewing machine switch 11 is turned on and reads the operation start signal, the sewing machine 1 shown in FIG. The sewing machine needle starts moving up and down as shown,
Sewing begins. 3 (C )
The pulse train shown in FIG. 2 is input to the pulse motor driver shown in FIG. 2, and the presser foot device is moved by a predetermined length by the pulse motor shown in FIG. 1 making 5 or 60 revolutions.

Next, in FIG. 2 showing the schematic configuration of the pulse motor driver, a pulse train C corresponding to the stitch length (FIG. 3 (C
) is input to the pulse motor driver, the phase switching circuit 24 selects the excitation phase and turns the phase switching transistor 23 on and off. And the heavy pressure comparison circuit 26
extracts the dead current value Il flowing through the pulse smoke coil 22 as the voltage of the current detection resistor 25, compares this voltage with the reference voltage 27, and outputs the error signal to the PWM 28. This PWMz8 is based on the reference oscillation from the reference oscillation circuit 29, controls the pulse width of the high frequency pulse using the error signal, switches the transistor 30, and performs constant current control.

Therefore, the normal pressure Eo (voltage of the DC power supply 31) shown in FIG. , the average voltage applied according to the width is El, and the average current at this time is If.

However, in the drive device of such an automatic sewing machine, the current II flowing through the coil 22 of the pulse motor
is constant regardless of whether the presser foot device is in operation or stopped. For this reason, when the moment of inertia of the presser foot device becomes large, such as during high-speed operation or when sewing heavy materials, the presser foot device operates during the cloth feeding period (see Figure 3(d)). Undershoot even after completion of steps (c) and (e) in ).

After repeating the overshoot, it reaches a predetermined position ((attenuation converges).

Therefore, when the sewing machine needle enters the material to be sewn, the force of the presser foot and the material to be sewn must be vibrating, and the stitch length may become unstable or the sewing quality may be poor. This method has the drawback of significantly lowering the quality of the sewing object.

[Summary of the invention]

In view of the above points, the present invention has been made to solve such problems and eliminate such drawbacks.The purpose of the present invention is to suppress the vibration of the presser foot device after the cloth feeding period is completed, and to improve the quality of seams. To provide a movement device for a self-sewing one-stitch sewing machine, which eliminates long-term instability and deterioration of sewing condition, and can obtain beautiful finished stitches and high-quality sewing stitches.

In order to achieve such an object, the present invention is equipped with a presser foot (6) that is activated when the positioning drive is stopped, increases the holding force when the device serving as the drive source of the positioning drive device is stopped, and suppresses damped vibration. It is designed so that you can learn how to do it.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 5 is a diagram showing an embodiment of a drive device for an automatic sewing machine according to the present invention, and is a block diagram showing an example of a pulse motor driver for the automatic sewing machine.

In FIG. 5, the same symbols as those in FIG.
It is configured to be input to the timer 34 at the same time as being input to the timer 34. 34a is configured to output "1) level" while the sending pulse train human power 33 is being input by a time constant determined by the output of the timer 34, the resistor 35, and the capacitor 36Ki.

37 is a reference voltage conversion circuit that switches the reference voltage of the voltage comparator circuit 26 by the output 34a from the timer 34;
By adding this reference pressure conversion circuit 37 to the Nockles motor driver, it is possible to stop the equipment that serves as the drive source for the positioning drive device. At the same time, it constitutes a means for increasing the holding force and suppressing damped vibration.

Next, the operation of the embodiment shown in FIG. 5 will be explained with reference to FIG. 6.

Figure 6 is a time chart for explaining the operation of Figure 5.
(a) to <c> are the same as (a) to (C) in Fig. 3, and (d) is the output 3 of the timer 34 in Fig. 5.
410 level state, (C) shows the thermal state of the presser foot device in the embodiment shown in FIG. 5, and (f) shows the reference voltage Vs obtained by the reference voltage conversion circuit 37 shown in FIG. It is.

As shown in FIG. 6(f), the cloth feeding stop period (
The base f#v pressure Vs in FIG.
is set higher than the reference box heavy pressure Vs' during the oil feeding period ((→, (see ladle) in Figure 6(C)), so V is set to reduce the voltage of the Tu pressure detection resistor 25. PWIQi 2
B switches transistor 30. For this reason,
%, pressure and oil' applied to pulse motor coil, 7i
As shown in Figure C7, which is an explanatory diagram showing the relationship of 1f,
Average pressure Bz applied to the coil 22 of the pulse motor
and average %M1:I 2 l, average 111 pressure El, average %' flow 1 during the cloth feeding period shown in Fig. 81'34.
Each value is larger than 1.

As a result, the pulse motor obtains a larger holding torque during the period when the cloth feed is stopped than during the period when the cloth feed is stopped. Vibration can be suppressed as shown in FIG. 6(e).

In the above embodiment, the reference voltage with which the voltage of the current detection resistor 25 is compared is converted in order to change the current value of the pulse motor coil. , switching the oscillation frequency of the difference ratio oscillation circuit 29.

Alternatively, the delay time of the PWM 28 may be changed, and vibrations of the sewing product caused by intermittent driving can be suppressed as in the above embodiment.

〔Effect of the invention〕

As explained above, according to the present invention, during the stop period of the intermittent drive of the presser foot, the holding torque of the pulse motor during the stop period of the cloth feeding device is used to stop the device known as the drive source of the positioning drive device. Since the holding force is increased by means of increasing the holding force and suppressing damped vibration, the vibration of the sewn product caused by intermittent drive is suppressed, thereby reducing instability of stitch length and sewing tension. The practical effects are extremely great because the deterioration is eliminated and high-quality sewn products with beautiful seams can be obtained.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an example of a drive device of a conventional automatic J-stitch sewing machine, Fig. 2 is a block diagram extracting the part related to the pulse motor driver from Fig. 1, and Figs. Fig. 4 is a time chart for explaining the operation of Fig. 2 and an explanatory diagram showing the relationship between the voltage applied to the pulse motor coil and the flowing current, and Fig. 5 is a pulse motor driver in the drive device of the automatic mt+stitch sewing machine according to the present invention. FIGS. 6 and 7 are a block diagram showing one embodiment of the present invention, and are a time chart for explaining the operation of FIG. 5, and explanatory diagrams showing the relationship between the heavy pressure applied to the pulse motor coil and the flowing current. 11...Fist sewing machine, 21111 battle detector, 3″@・
・Sewing machine motor, 4.・Fist/sewing machine drive lever, 5.6
...-Pulse motor, 8, 9... Nockles motor driver, 10... Transmission pulse train generation circuit, 11.
・11＠Sewing machine switch, 12･･･Paper foot switch, 1311＠Fist, CPU (control 1 configuration, 22･･･Pulse motor coil, 25･Fist, current detection resistor, 26･
...Voltage comparison circuit, 28...Pulse width control circuit,
34Φ...Timer, 31...Fist/Reference voltage conversion circuit. Agent Masuo Oiwa Figure 2 Figure 4 Figure 7 Figure 5 Figure 6 Procedure amendment (voluntary) 1. Display of the incident! i4' request No. 58-177523 2
, Title of the invention Automatic sewing electric machine drive device 3, Relationship with the case of the person making the amendment Patent applicant Hitoshi Katayama Department 4, Agent

Claims (2)

[Claims] (1) A sewing machine that forms stitches, a drive device that drives this sewing machine, a positioning drive device that positions a presser foot device that clamps a workpiece based on pre-programmed data, and control that controls each of these devices. In an automatic sewing machine that is provided with a device and drives the data passage intermittently in synchronization with the rotation of the sewing machine, the holding force is increased when a device serving as a drive source for the positioning drive device is stopped. A drive device for an automatic sewing machine, characterized in that it is equipped with means for suppressing damped vibration. (2) A means for increasing the holding force and suppressing damped vibration when the device serving as the drive source of the positioning drive device is stopped is to have the pulse motor driver extract the current flowing through the pulse motor coil that drives the presser foot device as a voltage. voltage and
Claim 1 is characterized in that the voltage comparator circuit is configured by adding a voltage comparison circuit for comparing the voltage obtained by a reference voltage conversion circuit that receives a feed pulse train as input, converts it to a reference pressure, and outputs the same. Drive device for automatic sewing machine.